This section provides background information related to the present disclosure which is not necessarily prior art.
Many exhaust systems have attempted to use both active and passive valve assemblies to alter the characteristics of exhaust flow through a conduit as the exhaust pressure increases due to increasing engine speed. Active valves carry the increased expense of requiring a specific actuating element, such as a solenoid. Passive valves utilize the pressure of the exhaust stream in the conduit with which the valve is associated.
Traditionally, even passive valves at their lower expense give rise to assembly problems when utilized with a tubular conduit in which they are to be mounted.
In one approach, when assembling such a flapper valve or snap-action valve plate inside the conduit, the axle is first inserted through openings on opposite sides of the conduit and then the valve flap must be welded to the axle while it is inside the tube. This requires provision of at least one access opening to receive a welding tool. Furthermore, a simple one-piece conduit with drilled holes for the axle also leads to potential rattling between the axle shaft and the holes leading to undesirable operating noise.
Another approach to assembling a flapper valve to a conduit is to utilize two conduit halves which are initially separated and slotted with notches with match up with each other to form closed perimeter axle receiving holes after the axle and valve have been inserted into one pair of the notches. The advantage of this approach is that the flap/axle can be assembled outside of the conduit and notches can be easily produced. However, this is countered by the disadvantage that it may be difficult to control the hole size for receipt of the axle. Additionally, support for any bushings surrounding the axle is confined to a narrow area.
In yet another prior approach, notches for the axle in the two pipe halves can be cut out and the two pipes are flanged and butted together but not overlapped. This presents a positive stop and maintains a consistent hole size. However, support for any axle bushing is too narrow and will cause the bushings to wear out prematurely.